1. Field of the Disclosure
This disclosure relates in general to electroluminescent complexes of Ir(III). It also relates to devices in which the Ir complex is an active component.
2. Description of the Related Art
Organic electronic devices define a category of products that include an active layer. Such devices convert electrical energy into radiation, detect signals through electronic processes, convert radiation into electrical energy, or include one or more organic semiconductor layers. Organic light-emitting diodes (OLEDs) are an organic electronic device comprising an organic layer capable of electroluminescence. In some OLEDs, these photoactive organic layers comprise simple organic molecules, conjugated polymers, or organometallic complexes. Such photoactive organic layers can be sandwiched between electrical contact layers. When a voltage is applied across these electrical contact layers, the organic layer emits light. The emission of light from the photoactive organic layers in OLEDs may be used, for example, in electrical displays and microelectronic devices.
It is well known to use organic electroluminescent compounds as the active component in LEDs. Simple organic molecules such as anthracene, thiadiazole derivatives, and coumarin derivatives are known to show electroluminescence. Semiconductive conjugated polymers have also been used as electroluminescent components, as has been disclosed in, for example, Friend et al., U.S. Pat. No. 5,247,190, Heeger et al.,
U.S. Pat. No. 5,408,109, and Nakano et al., Published European Patent Application 443 861. Complexes of 8 hydroxyquinolate with trivalent metal ions, particularly aluminum, have been extensively used as electroluminescent components, as has been disclosed in, for example, Tang et al., U.S. Pat. No. 5,552,678. Cyclometalated iridium and platinum electroluminescent compounds have been used as electroluminescent components, as has been disclosed in, for example, Petrov et al., U.S. Pat. No. 6,670,645 and Published PCT Applications WO 03/063555 and WO 2004/016710. The general use of β-diketimines is described in Lappert, M. F.; Severn, J. R.; Bourget-Merle, L. Chem. Rev. 2002, 102, 3031.
However, there is a continuing need for electroluminescent compounds.